Ticket #48146 - async simple paged results issue
    
    Description: commit 5e9c4f1f09596dd076a6c3a0bb419580e8fd705e broke the
    CI test case ticket47824_test.py.
    
    If the simple paged results search is operated on a backend having one
    or more sub-backends underneath, it fails to pick up the next sub-back
    ends, but repeats the search on the parent backend.  The problem was
    fixed.
    
    https://fedorahosted.org/389/ticket/48146
    
    Reviewed by mreynolds@redhat.com (Thank you, Mark!!)
    
    (cherry picked from commit 03d3455dfbe84f034a234df2ebd8cfdd7ad15f48)
    (cherry picked from commit f6fe5bfe4c1fb1402af789a0f935c765c299d103)
    (cherry picked from commit 64b54d416e75eaeb611ece982c1be9acf3f56161)